Fuel injection nozzle for internal combustion engines

ABSTRACT

A fuel injection nozzle for internal combustion engines which include a hollow screw for fastening the nozzle to the cylinder head of the engine. The nozzle further includes a nozzle holder into which an annular groove extends from the outer surface thereof. There is also provided a snap ring device which partially and radially engages the annular groove.

United States Patent Hofmann et al.

[451 Sept. 30, 1975 FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES [75] Inventors: Karl Hofmann, Aldingen; Walter Mladek, Stuttgart, both of Germany [73] Assignee: Robert Bosch G.m.b.H., Stuttgart,

Germany [22] Filed: Jan. 25, 1974 [21] Appl. N0.: 436.783

[30] Foreign Application Priority Data Jan. 25, I973 Germany 2303506 [52] U.S. Cl. 239/533 [51] Int. Cl.-' F02M 61/04 [58] Field of Search 239/533; 285/393, 415,

[561 References Cited UNITED STATES PATENTS l.()57.763 4/1913 Mueller ct al. 285/415 X l 925,937 9/1933 Schultis 285/356 X Primary E.\'aminerM. Henson Wood, Jr. Assistant E.\'aminerAndres Kashnikow Attorney, Agent, or Firm--Edwin E. Greigg [57] ABSTRACT A fuel injection nozzle for internal combustion engines which include a hollow screw for fastening the nozzle to the cylinder head of the engine. The nozzle further includes a nozzle holder into which an annular groove extends from the outer surface thereof. There is also provided a snap ring device which partially and radially engages the annular groove.

1 Claim, 1 Drawing Figure U.S. Patent Sept. 30,1975 3,908,911

FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The present invention relates to a fuel injection nozzle for internal combustion engines, and more particularly to a fuel injection nozzle having a hollow screw which bears against a device belonging to the nozzle holder and by means of which the nozzle may be fastened to the cylinder head of the internal combustion engine.

Because of the fact that the individual parts of a fuel injection nozzle. especially of a nozzle holder, are subjected during manufacture to stock removal processes, it is desired that the raw material to be used, consisting of round rods, have as small a diameter as possible, with the stock removal processes consisting, preferably, of pure turning and drilling operations.

In a known fuel injection nozzle of this type, the hollow screw for fastening the nozzle is supported on a flange of the nozzle holder which was obtained by'turning down the remainder of the shaft. It is furthermore desired that the developed nozzle holder be suitable not only for fastening by means of a hollow screw but also by means of flange brackets or other fastening members. for example, on a principle of assembly using prefabricated parts.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a fuel injection nozzle which accomplishes the above desired purposes.

This and other objects are attained according to the present invention in that the device is a snap ring which partially and radially engages an annular groove of the nozzle holder.

According to a special advantageous embodiment of the present invention, the hollow screw has an internal groove on its side facing the snap ring which covers a portion of the snap ring in its circumferential direction and secures it with respect to radial deflection. Preferably the internal groove may be tapered in the direction of the side facing away from the engine, and in this way the snap ring is radially tensioned when the injection nozzle is axially fastened.

BRIEF DESCRIPTION OF THE DRAWING An exemplary embodiment of the object of the present invention is shown in the sole FIGURE of the drawing which illustrates in partial cross section a fuel injection valve including the snap ring device.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the bore 1 of the cylinder head 2 of an internal combustion engine, a fuel injection nozzle 3 is fastened by means of a hollow screw 4. The hollow screw 4 bears on a snap ring 5, which is preferably circular in cross section with approximately one half of its circumferential entent engaging an annular groove 6 of the nozzle holder 7. The hollow screw 4 has an internal groove 8, which covers a portion of the snap ring 5 and which tapers axially so that when the nozzle is axially fastened, the snap ring is radially tensioned at the same time.

Aside from the fact that the holder according to the present invention makes possible an extremely favorable manufacture requiring few steps, it also permits other means for fastening the nozzle, for example, clamps or flanges. In such a case, only the annular groove 6 would additionally be present. Because of the fact that there is no shoulder serving as a support for the hollow screw 4 on the nozzle holder 7, an inserted alignment stud 10 can be maintained short enough so that it lies within the internal screw threads 11 or the cylinder intended to accept the hollow screw 4.

What is claimed is:

1. In a fuel injection nozzle which is fastened to a cylinder head of an internal combustion engine having a nozzle holder and a hollow screw.for fastening the nozzle to the cylinder head, the improvement comprising an annular groove extending into the nozzle holder from the outer surface thereof and a snap ring device which partially and radially engages the annual groove, said snap ring device having a circular cross section, wherein the hollow screw is provided with an internal groove extending into the hollow screw from the inner surface thereof, said internal groove covering a portion of the snap ring in its circumferential direction and securing it with respect to radial deflection, and wherein said internal groove is tapered in the axialdirection of the nozzle facing away from the engine such that the snap ring device is radially tensioned when the nozzle is axially fastened to the cylinder head.

l= l l 

1. In a fuel injection nozzle which is fastened to a cylinder head of an internal combustion engine having a nozzle holder and a hollow screw for fastening the nozzle to the cylinder head, the improvement comprising an annular groove extending into the nozzle holder from the outer surface thereof and a snap ring device which partially and radially engages the annual groove, said snap ring device having a circular cross section, wherein the hollow screw is provided with an internal groove extending into the hollow screw from the inner surface thereof, said internal groove covering a portion of the snap ring in its circumferential direction and securing it with respect to radial deflection, and wherein said internal groove is tapered in the axial direction of the nozzle facing away from the engine such that the snap ring device is radially tensioned when the nozzle is axially fastened to the cylinder head. 